nfsd: nfsd should drop CAP_MKNOD for non-root

[safe/jmp/linux-2.6] / drivers / ieee1394 / nodemgr.c

/*
 * Node information (ConfigROM) collection and management.
 *
 * Copyright (C) 2000           Andreas E. Bombe
 *               2001-2003      Ben Collins <bcollins@debian.net>
 *
 * This code is licensed under the GPL.  See the file COPYING in the root
 * directory of the kernel sources for details.
 */

#include <linux/bitmap.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/semaphore.h>
#include <asm/atomic.h>

#include "csr.h"
#include "highlevel.h"
#include "hosts.h"
#include "ieee1394.h"
#include "ieee1394_core.h"
#include "ieee1394_hotplug.h"
#include "ieee1394_types.h"
#include "ieee1394_transactions.h"
#include "nodemgr.h"

static int ignore_drivers;
module_param(ignore_drivers, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(ignore_drivers, "Disable automatic probing for drivers.");

struct nodemgr_csr_info {
        struct hpsb_host *host;
        nodeid_t nodeid;
        unsigned int generation;
        unsigned int speed_unverified:1;
};


/*
 * Correct the speed map entry.  This is necessary
 *  - for nodes with link speed < phy speed,
 *  - for 1394b nodes with negotiated phy port speed < IEEE1394_SPEED_MAX.
 * A possible speed is determined by trial and error, using quadlet reads.
 */
static int nodemgr_check_speed(struct nodemgr_csr_info *ci, u64 addr,
                               quadlet_t *buffer)
{
        quadlet_t q;
        u8 i, *speed, old_speed, good_speed;
        int error;

        speed = &(ci->host->speed[NODEID_TO_NODE(ci->nodeid)]);
        old_speed = *speed;
        good_speed = IEEE1394_SPEED_MAX + 1;

        /* Try every speed from S100 to old_speed.
         * If we did it the other way around, a too low speed could be caught
         * if the retry succeeded for some other reason, e.g. because the link
         * just finished its initialization. */
        for (i = IEEE1394_SPEED_100; i <= old_speed; i++) {
                *speed = i;
                error = hpsb_read(ci->host, ci->nodeid, ci->generation, addr,
                                  &q, 4);
                if (error)
                        break;
                *buffer = q;
                good_speed = i;
        }
        if (good_speed <= IEEE1394_SPEED_MAX) {
                HPSB_DEBUG("Speed probe of node " NODE_BUS_FMT " yields %s",
                           NODE_BUS_ARGS(ci->host, ci->nodeid),
                           hpsb_speedto_str[good_speed]);
                *speed = good_speed;
                ci->speed_unverified = 0;
                return 0;
        }
        *speed = old_speed;
        return error;
}

static int nodemgr_bus_read(struct csr1212_csr *csr, u64 addr,
                            void *buffer, void *__ci)
{
        struct nodemgr_csr_info *ci = (struct nodemgr_csr_info*)__ci;
        int i, error;

        for (i = 1; ; i++) {
                error = hpsb_read(ci->host, ci->nodeid, ci->generation, addr,
                                  buffer, 4);
                if (!error) {
                        ci->speed_unverified = 0;
                        break;
                }
                /* Give up after 3rd failure. */
                if (i == 3)
                        break;

                /* The ieee1394_core guessed the node's speed capability from
                 * the self ID.  Check whether a lower speed works. */
                if (ci->speed_unverified) {
                        error = nodemgr_check_speed(ci, addr, buffer);
                        if (!error)
                                break;
                }
                if (msleep_interruptible(334))
                        return -EINTR;
        }
        return error;
}

static struct csr1212_bus_ops nodemgr_csr_ops = {
        .bus_read =     nodemgr_bus_read,
};


/*
 * Basically what we do here is start off retrieving the bus_info block.
 * From there will fill in some info about the node, verify it is of IEEE
 * 1394 type, and that the crc checks out ok. After that we start off with
 * the root directory, and subdirectories. To do this, we retrieve the
 * quadlet header for a directory, find out the length, and retrieve the
 * complete directory entry (be it a leaf or a directory). We then process
 * it and add the info to our structure for that particular node.
 *
 * We verify CRC's along the way for each directory/block/leaf. The entire
 * node structure is generic, and simply stores the information in a way
 * that's easy to parse by the protocol interface.
 */

/*
 * The nodemgr relies heavily on the Driver Model for device callbacks and
 * driver/device mappings. The old nodemgr used to handle all this itself,
 * but now we are much simpler because of the LDM.
 */

struct host_info {
        struct hpsb_host *host;
        struct list_head list;
        struct task_struct *thread;
};

static int nodemgr_bus_match(struct device * dev, struct device_driver * drv);
static int nodemgr_uevent(struct device *dev, struct kobj_uevent_env *env);

struct bus_type ieee1394_bus_type = {
        .name           = "ieee1394",
        .match          = nodemgr_bus_match,
};

static void host_cls_release(struct device *dev)
{
        put_device(&container_of((dev), struct hpsb_host, host_dev)->device);
}

struct class hpsb_host_class = {
        .name           = "ieee1394_host",
        .dev_release    = host_cls_release,
};

static void ne_cls_release(struct device *dev)
{
        put_device(&container_of((dev), struct node_entry, node_dev)->device);
}

static struct class nodemgr_ne_class = {
        .name           = "ieee1394_node",
        .dev_release    = ne_cls_release,
};

static void ud_cls_release(struct device *dev)
{
        put_device(&container_of((dev), struct unit_directory, unit_dev)->device);
}

/* The name here is only so that unit directory hotplug works with old
 * style hotplug, which only ever did unit directories anyway.
 */
static struct class nodemgr_ud_class = {
        .name           = "ieee1394",
        .dev_release    = ud_cls_release,
        .dev_uevent     = nodemgr_uevent,
};

static struct hpsb_highlevel nodemgr_highlevel;


static void nodemgr_release_ud(struct device *dev)
{
        struct unit_directory *ud = container_of(dev, struct unit_directory, device);

        if (ud->vendor_name_kv)
                csr1212_release_keyval(ud->vendor_name_kv);
        if (ud->model_name_kv)
                csr1212_release_keyval(ud->model_name_kv);

        kfree(ud);
}

static void nodemgr_release_ne(struct device *dev)
{
        struct node_entry *ne = container_of(dev, struct node_entry, device);

        if (ne->vendor_name_kv)
                csr1212_release_keyval(ne->vendor_name_kv);

        kfree(ne);
}


static void nodemgr_release_host(struct device *dev)
{
        struct hpsb_host *host = container_of(dev, struct hpsb_host, device);

        csr1212_destroy_csr(host->csr.rom);

        kfree(host);
}

static int nodemgr_ud_platform_data;

static struct device nodemgr_dev_template_ud = {
        .bus            = &ieee1394_bus_type,
        .release        = nodemgr_release_ud,
        .platform_data  = &nodemgr_ud_platform_data,
};

static struct device nodemgr_dev_template_ne = {
        .bus            = &ieee1394_bus_type,
        .release        = nodemgr_release_ne,
};

/* This dummy driver prevents the host devices from being scanned. We have no
 * useful drivers for them yet, and there would be a deadlock possible if the
 * driver core scans the host device while the host's low-level driver (i.e.
 * the host's parent device) is being removed. */
static struct device_driver nodemgr_mid_layer_driver = {
        .bus            = &ieee1394_bus_type,
        .name           = "nodemgr",
        .owner          = THIS_MODULE,
};

struct device nodemgr_dev_template_host = {
        .bus            = &ieee1394_bus_type,
        .release        = nodemgr_release_host,
};


#define fw_attr(class, class_type, field, type, format_string)          \
static ssize_t fw_show_##class##_##field (struct device *dev, struct device_attribute *attr, char *buf)\
{                                                                       \
        class_type *class;                                              \
        class = container_of(dev, class_type, device);                  \
        return sprintf(buf, format_string, (type)class->field);         \
}                                                                       \
static struct device_attribute dev_attr_##class##_##field = {           \
        .attr = {.name = __stringify(field), .mode = S_IRUGO },         \
        .show   = fw_show_##class##_##field,                            \
};

#define fw_attr_td(class, class_type, td_kv)                            \
static ssize_t fw_show_##class##_##td_kv (struct device *dev, struct device_attribute *attr, char *buf)\
{                                                                       \
        int len;                                                        \
        class_type *class = container_of(dev, class_type, device);      \
        len = (class->td_kv->value.leaf.len - 2) * sizeof(quadlet_t);   \
        memcpy(buf,                                                     \
               CSR1212_TEXTUAL_DESCRIPTOR_LEAF_DATA(class->td_kv),      \
               len);                                                    \
        while (buf[len - 1] == '\0')                                    \
                len--;                                                  \
        buf[len++] = '\n';                                              \
        buf[len] = '\0';                                                \
        return len;                                                     \
}                                                                       \
static struct device_attribute dev_attr_##class##_##td_kv = {           \
        .attr = {.name = __stringify(td_kv), .mode = S_IRUGO },         \
        .show   = fw_show_##class##_##td_kv,                            \
};


#define fw_drv_attr(field, type, format_string)                 \
static ssize_t fw_drv_show_##field (struct device_driver *drv, char *buf) \
{                                                               \
        struct hpsb_protocol_driver *driver;                    \
        driver = container_of(drv, struct hpsb_protocol_driver, driver); \
        return sprintf(buf, format_string, (type)driver->field);\
}                                                               \
static struct driver_attribute driver_attr_drv_##field = {      \
        .attr = {.name = __stringify(field), .mode = S_IRUGO }, \
        .show   = fw_drv_show_##field,                          \
};


static ssize_t fw_show_ne_bus_options(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct node_entry *ne = container_of(dev, struct node_entry, device);

        return sprintf(buf, "IRMC(%d) CMC(%d) ISC(%d) BMC(%d) PMC(%d) GEN(%d) "
                       "LSPD(%d) MAX_REC(%d) MAX_ROM(%d) CYC_CLK_ACC(%d)\n",
                       ne->busopt.irmc,
                       ne->busopt.cmc, ne->busopt.isc, ne->busopt.bmc,
                       ne->busopt.pmc, ne->busopt.generation, ne->busopt.lnkspd,
                       ne->busopt.max_rec,
                       ne->busopt.max_rom,
                       ne->busopt.cyc_clk_acc);
}
static DEVICE_ATTR(bus_options,S_IRUGO,fw_show_ne_bus_options,NULL);


#ifdef HPSB_DEBUG_TLABELS
static ssize_t fw_show_ne_tlabels_free(struct device *dev,
                                       struct device_attribute *attr, char *buf)
{
        struct node_entry *ne = container_of(dev, struct node_entry, device);
        unsigned long flags;
        unsigned long *tp = ne->host->tl_pool[NODEID_TO_NODE(ne->nodeid)].map;
        int tf;

        spin_lock_irqsave(&hpsb_tlabel_lock, flags);
        tf = 64 - bitmap_weight(tp, 64);
        spin_unlock_irqrestore(&hpsb_tlabel_lock, flags);

        return sprintf(buf, "%d\n", tf);
}
static DEVICE_ATTR(tlabels_free,S_IRUGO,fw_show_ne_tlabels_free,NULL);


static ssize_t fw_show_ne_tlabels_mask(struct device *dev,
                                       struct device_attribute *attr, char *buf)
{
        struct node_entry *ne = container_of(dev, struct node_entry, device);
        unsigned long flags;
        unsigned long *tp = ne->host->tl_pool[NODEID_TO_NODE(ne->nodeid)].map;
        u64 tm;

        spin_lock_irqsave(&hpsb_tlabel_lock, flags);
#if (BITS_PER_LONG <= 32)
        tm = ((u64)tp[0] << 32) + tp[1];
#else
        tm = tp[0];
#endif
        spin_unlock_irqrestore(&hpsb_tlabel_lock, flags);

        return sprintf(buf, "0x%016llx\n", (unsigned long long)tm);
}
static DEVICE_ATTR(tlabels_mask, S_IRUGO, fw_show_ne_tlabels_mask, NULL);
#endif /* HPSB_DEBUG_TLABELS */


static ssize_t fw_set_ignore_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct unit_directory *ud = container_of(dev, struct unit_directory, device);
        int state = simple_strtoul(buf, NULL, 10);

        if (state == 1) {
                ud->ignore_driver = 1;
                device_release_driver(dev);
        } else if (state == 0)
                ud->ignore_driver = 0;

        return count;
}
static ssize_t fw_get_ignore_driver(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct unit_directory *ud = container_of(dev, struct unit_directory, device);

        return sprintf(buf, "%d\n", ud->ignore_driver);
}
static DEVICE_ATTR(ignore_driver, S_IWUSR | S_IRUGO, fw_get_ignore_driver, fw_set_ignore_driver);


static ssize_t fw_set_rescan(struct bus_type *bus, const char *buf,
                             size_t count)
{
        int error = 0;

        if (simple_strtoul(buf, NULL, 10) == 1)
                error = bus_rescan_devices(&ieee1394_bus_type);
        return error ? error : count;
}
static ssize_t fw_get_rescan(struct bus_type *bus, char *buf)
{
        return sprintf(buf, "You can force a rescan of the bus for "
                        "drivers by writing a 1 to this file\n");
}
static BUS_ATTR(rescan, S_IWUSR | S_IRUGO, fw_get_rescan, fw_set_rescan);


static ssize_t fw_set_ignore_drivers(struct bus_type *bus, const char *buf, size_t count)
{
        int state = simple_strtoul(buf, NULL, 10);

        if (state == 1)
                ignore_drivers = 1;
        else if (state == 0)
                ignore_drivers = 0;

        return count;
}
static ssize_t fw_get_ignore_drivers(struct bus_type *bus, char *buf)
{
        return sprintf(buf, "%d\n", ignore_drivers);
}
static BUS_ATTR(ignore_drivers, S_IWUSR | S_IRUGO, fw_get_ignore_drivers, fw_set_ignore_drivers);


struct bus_attribute *const fw_bus_attrs[] = {
        &bus_attr_rescan,
        &bus_attr_ignore_drivers,
        NULL
};


fw_attr(ne, struct node_entry, capabilities, unsigned int, "0x%06x\n")
fw_attr(ne, struct node_entry, nodeid, unsigned int, "0x%04x\n")

fw_attr(ne, struct node_entry, vendor_id, unsigned int, "0x%06x\n")
fw_attr_td(ne, struct node_entry, vendor_name_kv)

fw_attr(ne, struct node_entry, guid, unsigned long long, "0x%016Lx\n")
fw_attr(ne, struct node_entry, guid_vendor_id, unsigned int, "0x%06x\n")
fw_attr(ne, struct node_entry, in_limbo, int, "%d\n");

static struct device_attribute *const fw_ne_attrs[] = {
        &dev_attr_ne_guid,
        &dev_attr_ne_guid_vendor_id,
        &dev_attr_ne_capabilities,
        &dev_attr_ne_vendor_id,
        &dev_attr_ne_nodeid,
        &dev_attr_bus_options,
#ifdef HPSB_DEBUG_TLABELS
        &dev_attr_tlabels_free,
        &dev_attr_tlabels_mask,
#endif
};



fw_attr(ud, struct unit_directory, address, unsigned long long, "0x%016Lx\n")
fw_attr(ud, struct unit_directory, length, int, "%d\n")
/* These are all dependent on the value being provided */
fw_attr(ud, struct unit_directory, vendor_id, unsigned int, "0x%06x\n")
fw_attr(ud, struct unit_directory, model_id, unsigned int, "0x%06x\n")
fw_attr(ud, struct unit_directory, specifier_id, unsigned int, "0x%06x\n")
fw_attr(ud, struct unit_directory, version, unsigned int, "0x%06x\n")
fw_attr_td(ud, struct unit_directory, vendor_name_kv)
fw_attr_td(ud, struct unit_directory, model_name_kv)

static struct device_attribute *const fw_ud_attrs[] = {
        &dev_attr_ud_address,
        &dev_attr_ud_length,
        &dev_attr_ignore_driver,
};


fw_attr(host, struct hpsb_host, node_count, int, "%d\n")
fw_attr(host, struct hpsb_host, selfid_count, int, "%d\n")
fw_attr(host, struct hpsb_host, nodes_active, int, "%d\n")
fw_attr(host, struct hpsb_host, in_bus_reset, int, "%d\n")
fw_attr(host, struct hpsb_host, is_root, int, "%d\n")
fw_attr(host, struct hpsb_host, is_cycmst, int, "%d\n")
fw_attr(host, struct hpsb_host, is_irm, int, "%d\n")
fw_attr(host, struct hpsb_host, is_busmgr, int, "%d\n")

static struct device_attribute *const fw_host_attrs[] = {
        &dev_attr_host_node_count,
        &dev_attr_host_selfid_count,
        &dev_attr_host_nodes_active,
        &dev_attr_host_in_bus_reset,
        &dev_attr_host_is_root,
        &dev_attr_host_is_cycmst,
        &dev_attr_host_is_irm,
        &dev_attr_host_is_busmgr,
};


static ssize_t fw_show_drv_device_ids(struct device_driver *drv, char *buf)
{
        struct hpsb_protocol_driver *driver;
        struct ieee1394_device_id *id;
        int length = 0;
        char *scratch = buf;

        driver = container_of(drv, struct hpsb_protocol_driver, driver);
        id = driver->id_table;
        if (!id)
                return 0;

        for (; id->match_flags != 0; id++) {
                int need_coma = 0;

                if (id->match_flags & IEEE1394_MATCH_VENDOR_ID) {
                        length += sprintf(scratch, "vendor_id=0x%06x", id->vendor_id);
                        scratch = buf + length;
                        need_coma++;
                }

                if (id->match_flags & IEEE1394_MATCH_MODEL_ID) {
                        length += sprintf(scratch, "%smodel_id=0x%06x",
                                          need_coma++ ? "," : "",
                                          id->model_id);
                        scratch = buf + length;
                }

                if (id->match_flags & IEEE1394_MATCH_SPECIFIER_ID) {
                        length += sprintf(scratch, "%sspecifier_id=0x%06x",
                                          need_coma++ ? "," : "",
                                          id->specifier_id);
                        scratch = buf + length;
                }

                if (id->match_flags & IEEE1394_MATCH_VERSION) {
                        length += sprintf(scratch, "%sversion=0x%06x",
                                          need_coma++ ? "," : "",
                                          id->version);
                        scratch = buf + length;
                }

                if (need_coma) {
                        *scratch++ = '\n';
                        length++;
                }
        }

        return length;
}
static DRIVER_ATTR(device_ids,S_IRUGO,fw_show_drv_device_ids,NULL);


fw_drv_attr(name, const char *, "%s\n")

static struct driver_attribute *const fw_drv_attrs[] = {
        &driver_attr_drv_name,
        &driver_attr_device_ids,
};


static void nodemgr_create_drv_files(struct hpsb_protocol_driver *driver)
{
        struct device_driver *drv = &driver->driver;
        int i;

        for (i = 0; i < ARRAY_SIZE(fw_drv_attrs); i++)
                if (driver_create_file(drv, fw_drv_attrs[i]))
                        goto fail;
        return;
fail:
        HPSB_ERR("Failed to add sysfs attribute");
}


static void nodemgr_remove_drv_files(struct hpsb_protocol_driver *driver)
{
        struct device_driver *drv = &driver->driver;
        int i;

        for (i = 0; i < ARRAY_SIZE(fw_drv_attrs); i++)
                driver_remove_file(drv, fw_drv_attrs[i]);
}


static void nodemgr_create_ne_dev_files(struct node_entry *ne)
{
        struct device *dev = &ne->device;
        int i;

        for (i = 0; i < ARRAY_SIZE(fw_ne_attrs); i++)
                if (device_create_file(dev, fw_ne_attrs[i]))
                        goto fail;
        return;
fail:
        HPSB_ERR("Failed to add sysfs attribute");
}


static void nodemgr_create_host_dev_files(struct hpsb_host *host)
{
        struct device *dev = &host->device;
        int i;

        for (i = 0; i < ARRAY_SIZE(fw_host_attrs); i++)
                if (device_create_file(dev, fw_host_attrs[i]))
                        goto fail;
        return;
fail:
        HPSB_ERR("Failed to add sysfs attribute");
}


static struct node_entry *find_entry_by_nodeid(struct hpsb_host *host,
                                               nodeid_t nodeid);

static void nodemgr_update_host_dev_links(struct hpsb_host *host)
{
        struct device *dev = &host->device;
        struct node_entry *ne;

        sysfs_remove_link(&dev->kobj, "irm_id");
        sysfs_remove_link(&dev->kobj, "busmgr_id");
        sysfs_remove_link(&dev->kobj, "host_id");

        if ((ne = find_entry_by_nodeid(host, host->irm_id)) &&
            sysfs_create_link(&dev->kobj, &ne->device.kobj, "irm_id"))
                goto fail;
        if ((ne = find_entry_by_nodeid(host, host->busmgr_id)) &&
            sysfs_create_link(&dev->kobj, &ne->device.kobj, "busmgr_id"))
                goto fail;
        if ((ne = find_entry_by_nodeid(host, host->node_id)) &&
            sysfs_create_link(&dev->kobj, &ne->device.kobj, "host_id"))
                goto fail;
        return;
fail:
        HPSB_ERR("Failed to update sysfs attributes for host %d", host->id);
}

static void nodemgr_create_ud_dev_files(struct unit_directory *ud)
{
        struct device *dev = &ud->device;
        int i;

        for (i = 0; i < ARRAY_SIZE(fw_ud_attrs); i++)
                if (device_create_file(dev, fw_ud_attrs[i]))
                        goto fail;
        if (ud->flags & UNIT_DIRECTORY_SPECIFIER_ID)
                if (device_create_file(dev, &dev_attr_ud_specifier_id))
                        goto fail;
        if (ud->flags & UNIT_DIRECTORY_VERSION)
                if (device_create_file(dev, &dev_attr_ud_version))
                        goto fail;
        if (ud->flags & UNIT_DIRECTORY_VENDOR_ID) {
                if (device_create_file(dev, &dev_attr_ud_vendor_id))
                        goto fail;
                if (ud->vendor_name_kv &&
                    device_create_file(dev, &dev_attr_ud_vendor_name_kv))
                        goto fail;
        }
        if (ud->flags & UNIT_DIRECTORY_MODEL_ID) {
                if (device_create_file(dev, &dev_attr_ud_model_id))
                        goto fail;
                if (ud->model_name_kv &&
                    device_create_file(dev, &dev_attr_ud_model_name_kv))
                        goto fail;
        }
        return;
fail:
        HPSB_ERR("Failed to add sysfs attribute");
}


static int nodemgr_bus_match(struct device * dev, struct device_driver * drv)
{
        struct hpsb_protocol_driver *driver;
        struct unit_directory *ud;
        struct ieee1394_device_id *id;

        /* We only match unit directories */
        if (dev->platform_data != &nodemgr_ud_platform_data)
                return 0;

        ud = container_of(dev, struct unit_directory, device);
        if (ud->ne->in_limbo || ud->ignore_driver)
                return 0;

        /* We only match drivers of type hpsb_protocol_driver */
        if (drv == &nodemgr_mid_layer_driver)
                return 0;

        driver = container_of(drv, struct hpsb_protocol_driver, driver);
        id = driver->id_table;
        if (!id)
                return 0;

        for (; id->match_flags != 0; id++) {
                if ((id->match_flags & IEEE1394_MATCH_VENDOR_ID) &&
                    id->vendor_id != ud->vendor_id)
                        continue;

                if ((id->match_flags & IEEE1394_MATCH_MODEL_ID) &&
                    id->model_id != ud->model_id)
                        continue;

                if ((id->match_flags & IEEE1394_MATCH_SPECIFIER_ID) &&
                    id->specifier_id != ud->specifier_id)
                        continue;

                if ((id->match_flags & IEEE1394_MATCH_VERSION) &&
                    id->version != ud->version)
                        continue;

                return 1;
        }

        return 0;
}


static DEFINE_MUTEX(nodemgr_serialize_remove_uds);

static int match_ne(struct device *dev, void *data)
{
        struct unit_directory *ud;
        struct node_entry *ne = data;

        ud = container_of(dev, struct unit_directory, unit_dev);
        return ud->ne == ne;
}

static void nodemgr_remove_uds(struct node_entry *ne)
{
        struct device *dev;
        struct unit_directory *ud;

        /* Use class_find device to iterate the devices. Since this code
         * may be called from other contexts besides the knodemgrds,
         * protect it by nodemgr_serialize_remove_uds.
         */
        mutex_lock(&nodemgr_serialize_remove_uds);
        for (;;) {
                dev = class_find_device(&nodemgr_ud_class, NULL, ne, match_ne);
                if (!dev)
                        break;
                ud = container_of(dev, struct unit_directory, unit_dev);
                put_device(dev);
                device_unregister(&ud->unit_dev);
                device_unregister(&ud->device);
        }
        mutex_unlock(&nodemgr_serialize_remove_uds);
}


static void nodemgr_remove_ne(struct node_entry *ne)
{
        struct device *dev;

        dev = get_device(&ne->device);
        if (!dev)
                return;

        HPSB_DEBUG("Node removed: ID:BUS[" NODE_BUS_FMT "]  GUID[%016Lx]",
                   NODE_BUS_ARGS(ne->host, ne->nodeid), (unsigned long long)ne->guid);
        nodemgr_remove_uds(ne);

        device_unregister(&ne->node_dev);
        device_unregister(dev);

        put_device(dev);
}

static int remove_host_dev(struct device *dev, void *data)
{
        if (dev->bus == &ieee1394_bus_type)
                nodemgr_remove_ne(container_of(dev, struct node_entry,
                                  device));
        return 0;
}

static void nodemgr_remove_host_dev(struct device *dev)
{
        device_for_each_child(dev, NULL, remove_host_dev);
        sysfs_remove_link(&dev->kobj, "irm_id");
        sysfs_remove_link(&dev->kobj, "busmgr_id");
        sysfs_remove_link(&dev->kobj, "host_id");
}


static void nodemgr_update_bus_options(struct node_entry *ne)
{
#ifdef CONFIG_IEEE1394_VERBOSEDEBUG
        static const u16 mr[] = { 4, 64, 1024, 0};
#endif
        quadlet_t busoptions = be32_to_cpu(ne->csr->bus_info_data[2]);

        ne->busopt.irmc         = (busoptions >> 31) & 1;
        ne->busopt.cmc          = (busoptions >> 30) & 1;
        ne->busopt.isc          = (busoptions >> 29) & 1;
        ne->busopt.bmc          = (busoptions >> 28) & 1;
        ne->busopt.pmc          = (busoptions >> 27) & 1;
        ne->busopt.cyc_clk_acc  = (busoptions >> 16) & 0xff;
        ne->busopt.max_rec      = 1 << (((busoptions >> 12) & 0xf) + 1);
        ne->busopt.max_rom      = (busoptions >> 8) & 0x3;
        ne->busopt.generation   = (busoptions >> 4) & 0xf;
        ne->busopt.lnkspd       = busoptions & 0x7;

        HPSB_VERBOSE("NodeMgr: raw=0x%08x irmc=%d cmc=%d isc=%d bmc=%d pmc=%d "
                     "cyc_clk_acc=%d max_rec=%d max_rom=%d gen=%d lspd=%d",
                     busoptions, ne->busopt.irmc, ne->busopt.cmc,
                     ne->busopt.isc, ne->busopt.bmc, ne->busopt.pmc,
                     ne->busopt.cyc_clk_acc, ne->busopt.max_rec,
                     mr[ne->busopt.max_rom],
                     ne->busopt.generation, ne->busopt.lnkspd);
}


static struct node_entry *nodemgr_create_node(octlet_t guid,
                                struct csr1212_csr *csr, struct hpsb_host *host,
                                nodeid_t nodeid, unsigned int generation)
{
        struct node_entry *ne;

        ne = kzalloc(sizeof(*ne), GFP_KERNEL);
        if (!ne)
                goto fail_alloc;

        ne->host = host;
        ne->nodeid = nodeid;
        ne->generation = generation;
        ne->needs_probe = true;

        ne->guid = guid;
        ne->guid_vendor_id = (guid >> 40) & 0xffffff;
        ne->csr = csr;

        memcpy(&ne->device, &nodemgr_dev_template_ne,
               sizeof(ne->device));
        ne->device.parent = &host->device;
        dev_set_name(&ne->device, "%016Lx", (unsigned long long)(ne->guid));

        ne->node_dev.parent = &ne->device;
        ne->node_dev.class = &nodemgr_ne_class;
        dev_set_name(&ne->node_dev, "%016Lx", (unsigned long long)(ne->guid));

        if (device_register(&ne->device))
                goto fail_devreg;
        if (device_register(&ne->node_dev))
                goto fail_classdevreg;
        get_device(&ne->device);

        nodemgr_create_ne_dev_files(ne);

        nodemgr_update_bus_options(ne);

        HPSB_DEBUG("%s added: ID:BUS[" NODE_BUS_FMT "]  GUID[%016Lx]",
                   (host->node_id == nodeid) ? "Host" : "Node",
                   NODE_BUS_ARGS(host, nodeid), (unsigned long long)guid);

        return ne;

fail_classdevreg:
        device_unregister(&ne->device);
fail_devreg:
        kfree(ne);
fail_alloc:
        HPSB_ERR("Failed to create node ID:BUS[" NODE_BUS_FMT "]  GUID[%016Lx]",
                 NODE_BUS_ARGS(host, nodeid), (unsigned long long)guid);

        return NULL;
}

static int match_ne_guid(struct device *dev, void *data)
{
        struct node_entry *ne;
        u64 *guid = data;

        ne = container_of(dev, struct node_entry, node_dev);
        return ne->guid == *guid;
}

static struct node_entry *find_entry_by_guid(u64 guid)
{
        struct device *dev;
        struct node_entry *ne;

        dev = class_find_device(&nodemgr_ne_class, NULL, &guid, match_ne_guid);
        if (!dev)
                return NULL;
        ne = container_of(dev, struct node_entry, node_dev);
        put_device(dev);

        return ne;
}

struct match_nodeid_parameter {
        struct hpsb_host *host;
        nodeid_t nodeid;
};

static int match_ne_nodeid(struct device *dev, void *data)
{
        int found = 0;
        struct node_entry *ne;
        struct match_nodeid_parameter *p = data;

        if (!dev)
                goto ret;
        ne = container_of(dev, struct node_entry, node_dev);
        if (ne->host == p->host && ne->nodeid == p->nodeid)
                found = 1;
ret:
        return found;
}

static struct node_entry *find_entry_by_nodeid(struct hpsb_host *host,
                                               nodeid_t nodeid)
{
        struct device *dev;
        struct node_entry *ne;
        struct match_nodeid_parameter p;

        p.host = host;
        p.nodeid = nodeid;

        dev = class_find_device(&nodemgr_ne_class, NULL, &p, match_ne_nodeid);
        if (!dev)
                return NULL;
        ne = container_of(dev, struct node_entry, node_dev);
        put_device(dev);

        return ne;
}


static void nodemgr_register_device(struct node_entry *ne, 
        struct unit_directory *ud, struct device *parent)
{
        memcpy(&ud->device, &nodemgr_dev_template_ud,
               sizeof(ud->device));

        ud->device.parent = parent;

        dev_set_name(&ud->device, "%s-%u", dev_name(&ne->device), ud->id);

        ud->unit_dev.parent = &ud->device;
        ud->unit_dev.class = &nodemgr_ud_class;
        dev_set_name(&ud->unit_dev, "%s-%u", dev_name(&ne->device), ud->id);

        if (device_register(&ud->device))
                goto fail_devreg;
        if (device_register(&ud->unit_dev))
                goto fail_classdevreg;
        get_device(&ud->device);

        nodemgr_create_ud_dev_files(ud);

        return;

fail_classdevreg:
        device_unregister(&ud->device);
fail_devreg:
        HPSB_ERR("Failed to create unit %s", dev_name(&ud->device));
}       


/* This implementation currently only scans the config rom and its
 * immediate unit directories looking for software_id and
 * software_version entries, in order to get driver autoloading working. */
static struct unit_directory *nodemgr_process_unit_directory
        (struct node_entry *ne, struct csr1212_keyval *ud_kv,
         unsigned int *id, struct unit_directory *parent)
{
        struct unit_directory *ud;
        struct unit_directory *ud_child = NULL;
        struct csr1212_dentry *dentry;
        struct csr1212_keyval *kv;
        u8 last_key_id = 0;

        ud = kzalloc(sizeof(*ud), GFP_KERNEL);
        if (!ud)
                goto unit_directory_error;

        ud->ne = ne;
        ud->ignore_driver = ignore_drivers;
        ud->address = ud_kv->offset + CSR1212_REGISTER_SPACE_BASE;
        ud->directory_id = ud->address & 0xffffff;
        ud->ud_kv = ud_kv;
        ud->id = (*id)++;

        /* inherit vendor_id from root directory if none exists in unit dir */
        ud->vendor_id = ne->vendor_id;

        csr1212_for_each_dir_entry(ne->csr, kv, ud_kv, dentry) {
                switch (kv->key.id) {
                case CSR1212_KV_ID_VENDOR:
                        if (kv->key.type == CSR1212_KV_TYPE_IMMEDIATE) {
                                ud->vendor_id = kv->value.immediate;
                                ud->flags |= UNIT_DIRECTORY_VENDOR_ID;
                        }
                        break;

                case CSR1212_KV_ID_MODEL:
                        ud->model_id = kv->value.immediate;
                        ud->flags |= UNIT_DIRECTORY_MODEL_ID;
                        break;

                case CSR1212_KV_ID_SPECIFIER_ID:
                        ud->specifier_id = kv->value.immediate;
                        ud->flags |= UNIT_DIRECTORY_SPECIFIER_ID;
                        break;

                case CSR1212_KV_ID_VERSION:
                        ud->version = kv->value.immediate;
                        ud->flags |= UNIT_DIRECTORY_VERSION;
                        break;

                case CSR1212_KV_ID_DESCRIPTOR:
                        if (kv->key.type == CSR1212_KV_TYPE_LEAF &&
                            CSR1212_DESCRIPTOR_LEAF_TYPE(kv) == 0 &&
                            CSR1212_DESCRIPTOR_LEAF_SPECIFIER_ID(kv) == 0 &&
                            CSR1212_TEXTUAL_DESCRIPTOR_LEAF_WIDTH(kv) == 0 &&
                            CSR1212_TEXTUAL_DESCRIPTOR_LEAF_CHAR_SET(kv) == 0 &&
                            CSR1212_TEXTUAL_DESCRIPTOR_LEAF_LANGUAGE(kv) == 0) {
                                switch (last_key_id) {
                                case CSR1212_KV_ID_VENDOR:
                                        csr1212_keep_keyval(kv);
                                        ud->vendor_name_kv = kv;
                                        break;

                                case CSR1212_KV_ID_MODEL:
                                        csr1212_keep_keyval(kv);
                                        ud->model_name_kv = kv;
                                        break;

                                }
                        } /* else if (kv->key.type == CSR1212_KV_TYPE_DIRECTORY) ... */
                        break;

                case CSR1212_KV_ID_DEPENDENT_INFO:
                        /* Logical Unit Number */
                        if (kv->key.type == CSR1212_KV_TYPE_IMMEDIATE) {
                                if (ud->flags & UNIT_DIRECTORY_HAS_LUN) {
                                        ud_child = kmemdup(ud, sizeof(*ud_child), GFP_KERNEL);
                                        if (!ud_child)
                                                goto unit_directory_error;
                                        nodemgr_register_device(ne, ud_child, &ne->device);
                                        ud_child = NULL;
                                        
                                        ud->id = (*id)++;
                                }
                                ud->lun = kv->value.immediate;
                                ud->flags |= UNIT_DIRECTORY_HAS_LUN;

                        /* Logical Unit Directory */
                        } else if (kv->key.type == CSR1212_KV_TYPE_DIRECTORY) {
                                /* This should really be done in SBP2 as this is
                                 * doing SBP2 specific parsing.
                                 */
                                
                                /* first register the parent unit */
                                ud->flags |= UNIT_DIRECTORY_HAS_LUN_DIRECTORY;
                                if (ud->device.bus != &ieee1394_bus_type)
                                        nodemgr_register_device(ne, ud, &ne->device);
                                
                                /* process the child unit */
                                ud_child = nodemgr_process_unit_directory(ne, kv, id, ud);

                                if (ud_child == NULL)
                                        break;
                                
                                /* inherit unspecified values, the driver core picks it up */
                                if ((ud->flags & UNIT_DIRECTORY_MODEL_ID) &&
                                    !(ud_child->flags & UNIT_DIRECTORY_MODEL_ID))
                                {
                                        ud_child->flags |=  UNIT_DIRECTORY_MODEL_ID;
                                        ud_child->model_id = ud->model_id;
                                }
                                if ((ud->flags & UNIT_DIRECTORY_SPECIFIER_ID) &&
                                    !(ud_child->flags & UNIT_DIRECTORY_SPECIFIER_ID))
                                {
                                        ud_child->flags |=  UNIT_DIRECTORY_SPECIFIER_ID;
                                        ud_child->specifier_id = ud->specifier_id;
                                }
                                if ((ud->flags & UNIT_DIRECTORY_VERSION) &&
                                    !(ud_child->flags & UNIT_DIRECTORY_VERSION))
                                {
                                        ud_child->flags |=  UNIT_DIRECTORY_VERSION;
                                        ud_child->version = ud->version;
                                }
                                
                                /* register the child unit */
                                ud_child->flags |= UNIT_DIRECTORY_LUN_DIRECTORY;
                                nodemgr_register_device(ne, ud_child, &ud->device);
                        }

                        break;

                case CSR1212_KV_ID_DIRECTORY_ID:
                        ud->directory_id = kv->value.immediate;
                        break;

                default:
                        break;
                }
                last_key_id = kv->key.id;
        }
        
        /* do not process child units here and only if not already registered */
        if (!parent && ud->device.bus != &ieee1394_bus_type)
                nodemgr_register_device(ne, ud, &ne->device);

        return ud;

unit_directory_error:
        kfree(ud);
        return NULL;
}


static void nodemgr_process_root_directory(struct node_entry *ne)
{
        unsigned int ud_id = 0;
        struct csr1212_dentry *dentry;
        struct csr1212_keyval *kv, *vendor_name_kv = NULL;
        u8 last_key_id = 0;

        ne->needs_probe = false;

        csr1212_for_each_dir_entry(ne->csr, kv, ne->csr->root_kv, dentry) {
                switch (kv->key.id) {
                case CSR1212_KV_ID_VENDOR:
                        ne->vendor_id = kv->value.immediate;
                        break;

                case CSR1212_KV_ID_NODE_CAPABILITIES:
                        ne->capabilities = kv->value.immediate;
                        break;

                case CSR1212_KV_ID_UNIT:
                        nodemgr_process_unit_directory(ne, kv, &ud_id, NULL);
                        break;

                case CSR1212_KV_ID_DESCRIPTOR:
                        if (last_key_id == CSR1212_KV_ID_VENDOR) {
                                if (kv->key.type == CSR1212_KV_TYPE_LEAF &&
                                    CSR1212_DESCRIPTOR_LEAF_TYPE(kv) == 0 &&
                                    CSR1212_DESCRIPTOR_LEAF_SPECIFIER_ID(kv) == 0 &&
                                    CSR1212_TEXTUAL_DESCRIPTOR_LEAF_WIDTH(kv) == 0 &&
                                    CSR1212_TEXTUAL_DESCRIPTOR_LEAF_CHAR_SET(kv) == 0 &&
                                    CSR1212_TEXTUAL_DESCRIPTOR_LEAF_LANGUAGE(kv) == 0) {
                                        csr1212_keep_keyval(kv);
                                        vendor_name_kv = kv;
                                }
                        }
                        break;
                }
                last_key_id = kv->key.id;
        }

        if (ne->vendor_name_kv) {
                kv = ne->vendor_name_kv;
                ne->vendor_name_kv = vendor_name_kv;
                csr1212_release_keyval(kv);
        } else if (vendor_name_kv) {
                ne->vendor_name_kv = vendor_name_kv;
                if (device_create_file(&ne->device,
                                       &dev_attr_ne_vendor_name_kv) != 0)
                        HPSB_ERR("Failed to add sysfs attribute");
        }
}

#ifdef CONFIG_HOTPLUG

static int nodemgr_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct unit_directory *ud;
        int retval = 0;
        /* ieee1394:venNmoNspNverN */
        char buf[8 + 1 + 3 + 8 + 2 + 8 + 2 + 8 + 3 + 8 + 1];

        if (!dev)
                return -ENODEV;

        ud = container_of(dev, struct unit_directory, unit_dev);

        if (ud->ne->in_limbo || ud->ignore_driver)
                return -ENODEV;

#define PUT_ENVP(fmt,val)                                       \
do {                                                            \
        retval = add_uevent_var(env, fmt, val);         \
        if (retval)                                             \
                return retval;                                  \
} while (0)

        PUT_ENVP("VENDOR_ID=%06x", ud->vendor_id);
        PUT_ENVP("MODEL_ID=%06x", ud->model_id);
        PUT_ENVP("GUID=%016Lx", (unsigned long long)ud->ne->guid);
        PUT_ENVP("SPECIFIER_ID=%06x", ud->specifier_id);
        PUT_ENVP("VERSION=%06x", ud->version);
        snprintf(buf, sizeof(buf), "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
                        ud->vendor_id,
                        ud->model_id,
                        ud->specifier_id,
                        ud->version);
        PUT_ENVP("MODALIAS=%s", buf);

#undef PUT_ENVP

        return 0;
}

#else

static int nodemgr_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        return -ENODEV;
}

#endif /* CONFIG_HOTPLUG */


int __hpsb_register_protocol(struct hpsb_protocol_driver *drv,
                             struct module *owner)
{
        int error;

        drv->driver.bus = &ieee1394_bus_type;
        drv->driver.owner = owner;
        drv->driver.name = drv->name;

        /* This will cause a probe for devices */
        error = driver_register(&drv->driver);
        if (!error)
                nodemgr_create_drv_files(drv);
        return error;
}

void hpsb_unregister_protocol(struct hpsb_protocol_driver *driver)
{
        nodemgr_remove_drv_files(driver);
        /* This will subsequently disconnect all devices that our driver
         * is attached to. */
        driver_unregister(&driver->driver);
}


/*
 * This function updates nodes that were present on the bus before the
 * reset and still are after the reset.  The nodeid and the config rom
 * may have changed, and the drivers managing this device must be
 * informed that this device just went through a bus reset, to allow
 * the to take whatever actions required.
 */
static void nodemgr_update_node(struct node_entry *ne, struct csr1212_csr *csr,
                                nodeid_t nodeid, unsigned int generation)
{
        if (ne->nodeid != nodeid) {
                HPSB_DEBUG("Node changed: " NODE_BUS_FMT " -> " NODE_BUS_FMT,
                           NODE_BUS_ARGS(ne->host, ne->nodeid),
                           NODE_BUS_ARGS(ne->host, nodeid));
                ne->nodeid = nodeid;
        }

        if (ne->busopt.generation != ((be32_to_cpu(csr->bus_info_data[2]) >> 4) & 0xf)) {
                kfree(ne->csr->private);
                csr1212_destroy_csr(ne->csr);
                ne->csr = csr;

                /* If the node's configrom generation has changed, we
                 * unregister all the unit directories. */
                nodemgr_remove_uds(ne);

                nodemgr_update_bus_options(ne);

                /* Mark the node as new, so it gets re-probed */
                ne->needs_probe = true;
        } else {
                /* old cache is valid, so update its generation */
                struct nodemgr_csr_info *ci = ne->csr->private;
                ci->generation = generation;
                /* free the partially filled now unneeded new cache */
                kfree(csr->private);
                csr1212_destroy_csr(csr);
        }

        /* Finally, mark the node current */
        smp_wmb();
        ne->generation = generation;

        if (ne->in_limbo) {
                device_remove_file(&ne->device, &dev_attr_ne_in_limbo);
                ne->in_limbo = false;

                HPSB_DEBUG("Node reactivated: "
                           "ID:BUS[" NODE_BUS_FMT "]  GUID[%016Lx]",
                           NODE_BUS_ARGS(ne->host, ne->nodeid),
                           (unsigned long long)ne->guid);
        }
}

static void nodemgr_node_scan_one(struct hpsb_host *host,
                                  nodeid_t nodeid, int generation)
{
        struct node_entry *ne;
        octlet_t guid;
        struct csr1212_csr *csr;
        struct nodemgr_csr_info *ci;
        u8 *speed;

        ci = kmalloc(sizeof(*ci), GFP_KERNEL);
        if (!ci)
                return;

        ci->host = host;
        ci->nodeid = nodeid;
        ci->generation = generation;

        /* Prepare for speed probe which occurs when reading the ROM */
        speed = &(host->speed[NODEID_TO_NODE(nodeid)]);
        if (*speed > host->csr.lnk_spd)
                *speed = host->csr.lnk_spd;
        ci->speed_unverified = *speed > IEEE1394_SPEED_100;

        /* We need to detect when the ConfigROM's generation has changed,
         * so we only update the node's info when it needs to be.  */

        csr = csr1212_create_csr(&nodemgr_csr_ops, 5 * sizeof(quadlet_t), ci);
        if (!csr || csr1212_parse_csr(csr) != CSR1212_SUCCESS) {
                HPSB_ERR("Error parsing configrom for node " NODE_BUS_FMT,
                         NODE_BUS_ARGS(host, nodeid));
                if (csr)
                        csr1212_destroy_csr(csr);
                kfree(ci);
                return;
        }

        if (csr->bus_info_data[1] != IEEE1394_BUSID_MAGIC) {
                /* This isn't a 1394 device, but we let it slide. There
                 * was a report of a device with broken firmware which
                 * reported '2394' instead of '1394', which is obviously a
                 * mistake. One would hope that a non-1394 device never
                 * gets connected to Firewire bus. If someone does, we
                 * shouldn't be held responsible, so we'll allow it with a
                 * warning.  */
                HPSB_WARN("Node " NODE_BUS_FMT " has invalid busID magic [0x%08x]",
                          NODE_BUS_ARGS(host, nodeid), csr->bus_info_data[1]);
        }

        guid = ((u64)be32_to_cpu(csr->bus_info_data[3]) << 32) | be32_to_cpu(csr->bus_info_data[4]);
        ne = find_entry_by_guid(guid);

        if (ne && ne->host != host && ne->in_limbo) {
                /* Must have moved this device from one host to another */
                nodemgr_remove_ne(ne);
                ne = NULL;
        }

        if (!ne)
                nodemgr_create_node(guid, csr, host, nodeid, generation);
        else
                nodemgr_update_node(ne, csr, nodeid, generation);
}


static void nodemgr_node_scan(struct hpsb_host *host, int generation)
{
        int count;
        struct selfid *sid = (struct selfid *)host->topology_map;
        nodeid_t nodeid = LOCAL_BUS;

        /* Scan each node on the bus */
        for (count = host->selfid_count; count; count--, sid++) {
                if (sid->extended)
                        continue;

                if (!sid->link_active) {
                        nodeid++;
                        continue;
                }
                nodemgr_node_scan_one(host, nodeid++, generation);
        }
}

static void nodemgr_pause_ne(struct node_entry *ne)
{
        HPSB_DEBUG("Node paused: ID:BUS[" NODE_BUS_FMT "]  GUID[%016Lx]",
                   NODE_BUS_ARGS(ne->host, ne->nodeid),
                   (unsigned long long)ne->guid);

        ne->in_limbo = true;
        WARN_ON(device_create_file(&ne->device, &dev_attr_ne_in_limbo));
}

static int update_pdrv(struct device *dev, void *data)
{
        struct unit_directory *ud;
        struct device_driver *drv;
        struct hpsb_protocol_driver *pdrv;
        struct node_entry *ne = data;
        int error;

        ud = container_of(dev, struct unit_directory, unit_dev);
        if (ud->ne == ne) {
                drv = get_driver(ud->device.driver);
                if (drv) {
                        error = 0;
                        pdrv = container_of(drv, struct hpsb_protocol_driver,
                                            driver);
                        if (pdrv->update) {
                                down(&ud->device.sem);
                                error = pdrv->update(ud);
                                up(&ud->device.sem);
                        }
                        if (error)
                                device_release_driver(&ud->device);
                        put_driver(drv);
                }
        }

        return 0;
}

static void nodemgr_update_pdrv(struct node_entry *ne)
{
        class_for_each_device(&nodemgr_ud_class, NULL, ne, update_pdrv);
}

/* Write the BROADCAST_CHANNEL as per IEEE1394a 8.3.2.3.11 and 8.4.2.3.  This
 * seems like an optional service but in the end it is practically mandatory
 * as a consequence of these clauses.
 *
 * Note that we cannot do a broadcast write to all nodes at once because some
 * pre-1394a devices would hang. */
static void nodemgr_irm_write_bc(struct node_entry *ne, int generation)
{
        const u64 bc_addr = (CSR_REGISTER_BASE | CSR_BROADCAST_CHANNEL);
        quadlet_t bc_remote, bc_local;
        int error;

        if (!ne->host->is_irm || ne->generation != generation ||
            ne->nodeid == ne->host->node_id)
                return;

        bc_local = cpu_to_be32(ne->host->csr.broadcast_channel);

        /* Check if the register is implemented and 1394a compliant. */
        error = hpsb_read(ne->host, ne->nodeid, generation, bc_addr, &bc_remote,
                          sizeof(bc_remote));
        if (!error && bc_remote & cpu_to_be32(0x80000000) &&
            bc_remote != bc_local)
                hpsb_node_write(ne, bc_addr, &bc_local, sizeof(bc_local));
}


static void nodemgr_probe_ne(struct hpsb_host *host, struct node_entry *ne,
                             int generation)
{
        struct device *dev;

        if (ne->host != host || ne->in_limbo)
                return;

        dev = get_device(&ne->device);
        if (!dev)
                return;

        nodemgr_irm_write_bc(ne, generation);

        /* If "needs_probe", then this is either a new or changed node we
         * rescan totally. If the generation matches for an existing node
         * (one that existed prior to the bus reset) we send update calls
         * down to the drivers. Otherwise, this is a dead node and we
         * suspend it. */
        if (ne->needs_probe)
                nodemgr_process_root_directory(ne);
        else if (ne->generation == generation)
                nodemgr_update_pdrv(ne);
        else
                nodemgr_pause_ne(ne);

        put_device(dev);
}

struct node_probe_parameter {
        struct hpsb_host *host;
        int generation;
        bool probe_now;
};

static int node_probe(struct device *dev, void *data)
{
        struct node_probe_parameter *p = data;
        struct node_entry *ne;

        if (p->generation != get_hpsb_generation(p->host))
                return -EAGAIN;

        ne = container_of(dev, struct node_entry, node_dev);
        if (ne->needs_probe == p->probe_now)
                nodemgr_probe_ne(p->host, ne, p->generation);
        return 0;
}

static int nodemgr_node_probe(struct hpsb_host *host, int generation)
{
        struct node_probe_parameter p;

        p.host = host;
        p.generation = generation;
        /*
         * Do some processing of the nodes we've probed. This pulls them
         * into the sysfs layer if needed, and can result in processing of
         * unit-directories, or just updating the node and it's
         * unit-directories.
         *
         * Run updates before probes. Usually, updates are time-critical
         * while probes are time-consuming.
         *
         * Meanwhile, another bus reset may have happened. In this case we
         * skip everything here and let the next bus scan handle it.
         * Otherwise we may prematurely remove nodes which are still there.
         */
        p.probe_now = false;
        if (class_for_each_device(&nodemgr_ne_class, NULL, &p, node_probe) != 0)
                return 0;

        p.probe_now = true;
        if (class_for_each_device(&nodemgr_ne_class, NULL, &p, node_probe) != 0)
                return 0;
        /*
         * Now let's tell the bus to rescan our devices. This may seem
         * like overhead, but the driver-model core will only scan a
         * device for a driver when either the device is added, or when a
         * new driver is added. A bus reset is a good reason to rescan
         * devices that were there before.  For example, an sbp2 device
         * may become available for login, if the host that held it was
         * just removed.
         */
        if (bus_rescan_devices(&ieee1394_bus_type) != 0)
                HPSB_DEBUG("bus_rescan_devices had an error");

        return 1;
}

static int remove_nodes_in_limbo(struct device *dev, void *data)
{
        struct node_entry *ne;

        if (dev->bus != &ieee1394_bus_type)
                return 0;

        ne = container_of(dev, struct node_entry, device);
        if (ne->in_limbo)
                nodemgr_remove_ne(ne);

        return 0;
}

static void nodemgr_remove_nodes_in_limbo(struct hpsb_host *host)
{
        device_for_each_child(&host->device, NULL, remove_nodes_in_limbo);
}

static int nodemgr_send_resume_packet(struct hpsb_host *host)
{
        struct hpsb_packet *packet;
        int error = -ENOMEM;

        packet = hpsb_make_phypacket(host,
                        EXTPHYPACKET_TYPE_RESUME |
                        NODEID_TO_NODE(host->node_id) << PHYPACKET_PORT_SHIFT);
        if (packet) {
                packet->no_waiter = 1;
                packet->generation = get_hpsb_generation(host);
                error = hpsb_send_packet(packet);
        }
        if (error)
                HPSB_WARN("fw-host%d: Failed to broadcast resume packet",
                          host->id);
        return error;
}

/* Perform a few high-level IRM responsibilities. */
static int nodemgr_do_irm_duties(struct hpsb_host *host, int cycles)
{
        quadlet_t bc;

        /* if irm_id == -1 then there is no IRM on this bus */
        if (!host->is_irm || host->irm_id == (nodeid_t)-1)
                return 1;

        /* We are a 1394a-2000 compliant IRM. Set the validity bit. */
        host->csr.broadcast_channel |= 0x40000000;

        /* If there is no bus manager then we should set the root node's
         * force_root bit to promote bus stability per the 1394
         * spec. (8.4.2.6) */
        if (host->busmgr_id == 0xffff && host->node_count > 1)
        {
                u16 root_node = host->node_count - 1;

                /* get cycle master capability flag from root node */
                if (host->is_cycmst ||
                    (!hpsb_read(host, LOCAL_BUS | root_node, get_hpsb_generation(host),
                                (CSR_REGISTER_BASE + CSR_CONFIG_ROM + 2 * sizeof(quadlet_t)),
                                &bc, sizeof(quadlet_t)) &&
                     be32_to_cpu(bc) & 1 << CSR_CMC_SHIFT))
                        hpsb_send_phy_config(host, root_node, -1);
                else {
                        HPSB_DEBUG("The root node is not cycle master capable; "
                                   "selecting a new root node and resetting...");

                        if (cycles >= 5) {
                                /* Oh screw it! Just leave the bus as it is */
                                HPSB_DEBUG("Stopping reset loop for IRM sanity");
                                return 1;
                        }

                        hpsb_send_phy_config(host, NODEID_TO_NODE(host->node_id), -1);
                        hpsb_reset_bus(host, LONG_RESET_FORCE_ROOT);

                        return 0;
                }
        }

        /* Some devices suspend their ports while being connected to an inactive
         * host adapter, i.e. if connected before the low-level driver is
         * loaded.  They become visible either when physically unplugged and
         * replugged, or when receiving a resume packet.  Send one once. */
        if (!host->resume_packet_sent && !nodemgr_send_resume_packet(host))
                host->resume_packet_sent = 1;

        return 1;
}

/* We need to ensure that if we are not the IRM, that the IRM node is capable of
 * everything we can do, otherwise issue a bus reset and try to become the IRM
 * ourselves. */
static int nodemgr_check_irm_capability(struct hpsb_host *host, int cycles)
{
        quadlet_t bc;
        int status;

        if (hpsb_disable_irm || host->is_irm)
                return 1;

        status = hpsb_read(host, LOCAL_BUS | (host->irm_id),
                           get_hpsb_generation(host),
                           (CSR_REGISTER_BASE | CSR_BROADCAST_CHANNEL),
                           &bc, sizeof(quadlet_t));

        if (status < 0 || !(be32_to_cpu(bc) & 0x80000000)) {
                /* The current irm node does not have a valid BROADCAST_CHANNEL
                 * register and we do, so reset the bus with force_root set */
                HPSB_DEBUG("Current remote IRM is not 1394a-2000 compliant, resetting...");

                if (cycles >= 5) {
                        /* Oh screw it! Just leave the bus as it is */
                        HPSB_DEBUG("Stopping reset loop for IRM sanity");
                        return 1;
                }

                hpsb_send_phy_config(host, NODEID_TO_NODE(host->node_id), -1);
                hpsb_reset_bus(host, LONG_RESET_FORCE_ROOT);

                return 0;
        }

        return 1;
}

static int nodemgr_host_thread(void *data)
{
        struct hpsb_host *host = data;
        unsigned int g, generation = 0;
        int i, reset_cycles = 0;

        set_freezable();
        /* Setup our device-model entries */
        nodemgr_create_host_dev_files(host);

        for (;;) {
                /* Sleep until next bus reset */
                set_current_state(TASK_INTERRUPTIBLE);
                if (get_hpsb_generation(host) == generation &&
                    !kthread_should_stop())
                        schedule();
                __set_current_state(TASK_RUNNING);

                /* Thread may have been woken up to freeze or to exit */
                if (try_to_freeze())
                        continue;
                if (kthread_should_stop())
                        goto exit;

                /* Pause for 1/4 second in 1/16 second intervals,
                 * to make sure things settle down. */
                g = get_hpsb_generation(host);
                for (i = 0; i < 4 ; i++) {
                        msleep_interruptible(63);
                        try_to_freeze();
                        if (kthread_should_stop())
                                goto exit;

                        /* Now get the generation in which the node ID's we collect
                         * are valid.  During the bus scan we will use this generation
                         * for the read transactions, so that if another reset occurs
                         * during the scan the transactions will fail instead of
                         * returning bogus data. */
                        generation = get_hpsb_generation(host);

                        /* If we get a reset before we are done waiting, then
                         * start the waiting over again */
                        if (generation != g)
                                g = generation, i = 0;
                }

                if (!nodemgr_check_irm_capability(host, reset_cycles) ||
                    !nodemgr_do_irm_duties(host, reset_cycles)) {
                        reset_cycles++;
                        continue;
                }
                reset_cycles = 0;

                /* Scan our nodes to get the bus options and create node
                 * entries. This does not do the sysfs stuff, since that
                 * would trigger uevents and such, which is a bad idea at
                 * this point. */
                nodemgr_node_scan(host, generation);

                /* This actually does the full probe, with sysfs
                 * registration. */
                if (!nodemgr_node_probe(host, generation))
                        continue;

                /* Update some of our sysfs symlinks */
                nodemgr_update_host_dev_links(host);

                /* Sleep 3 seconds */
                for (i = 3000/200; i; i--) {
                        msleep_interruptible(200);
                        try_to_freeze();
                        if (kthread_should_stop())
                                goto exit;

                        if (generation != get_hpsb_generation(host))
                                break;
                }
                /* Remove nodes which are gone, unless a bus reset happened */
                if (!i)
                        nodemgr_remove_nodes_in_limbo(host);
        }
exit:
        HPSB_VERBOSE("NodeMgr: Exiting thread");
        return 0;
}

struct per_host_parameter {
        void *data;
        int (*cb)(struct hpsb_host *, void *);
};

static int per_host(struct device *dev, void *data)
{
        struct hpsb_host *host;
        struct per_host_parameter *p = data;

        host = container_of(dev, struct hpsb_host, host_dev);
        return p->cb(host, p->data);
}

/**
 * nodemgr_for_each_host - call a function for each IEEE 1394 host
 * @data: an address to supply to the callback
 * @cb: function to call for each host
 *
 * Iterate the hosts, calling a given function with supplied data for each host.
 * If the callback fails on a host, i.e. if it returns a non-zero value, the
 * iteration is stopped.
 *
 * Return value: 0 on success, non-zero on failure (same as returned by last run
 * of the callback).
 */
int nodemgr_for_each_host(void *data, int (*cb)(struct hpsb_host *, void *))
{
        struct per_host_parameter p;

        p.cb = cb;
        p.data = data;
        return class_for_each_device(&hpsb_host_class, NULL, &p, per_host);
}

/* The following two convenience functions use a struct node_entry
 * for addressing a node on the bus.  They are intended for use by any
 * process context, not just the nodemgr thread, so we need to be a
 * little careful when reading out the node ID and generation.  The
 * thing that can go wrong is that we get the node ID, then a bus
 * reset occurs, and then we read the generation.  The node ID is
 * possibly invalid, but the generation is current, and we end up
 * sending a packet to a the wrong node.
 *
 * The solution is to make sure we read the generation first, so that
 * if a reset occurs in the process, we end up with a stale generation
 * and the transactions will fail instead of silently using wrong node
 * ID's.
 */

/**
 * hpsb_node_fill_packet - fill some destination information into a packet
 * @ne: destination node
 * @packet: packet to fill in
 *
 * This will fill in the given, pre-initialised hpsb_packet with the current
 * information from the node entry (host, node ID, bus generation number).
 */
void hpsb_node_fill_packet(struct node_entry *ne, struct hpsb_packet *packet)
{
        packet->host = ne->host;
        packet->generation = ne->generation;
        smp_rmb();
        packet->node_id = ne->nodeid;
}

int hpsb_node_write(struct node_entry *ne, u64 addr,
                    quadlet_t *buffer, size_t length)
{
        unsigned int generation = ne->generation;

        smp_rmb();
        return hpsb_write(ne->host, ne->nodeid, generation,
                          addr, buffer, length);
}

static void nodemgr_add_host(struct hpsb_host *host)
{
        struct host_info *hi;

        hi = hpsb_create_hostinfo(&nodemgr_highlevel, host, sizeof(*hi));
        if (!hi) {
                HPSB_ERR("NodeMgr: out of memory in add host");
                return;
        }
        hi->host = host;
        hi->thread = kthread_run(nodemgr_host_thread, host, "knodemgrd_%d",
                                 host->id);
        if (IS_ERR(hi->thread)) {
                HPSB_ERR("NodeMgr: cannot start thread for host %d", host->id);
                hpsb_destroy_hostinfo(&nodemgr_highlevel, host);
        }
}

static void nodemgr_host_reset(struct hpsb_host *host)
{
        struct host_info *hi = hpsb_get_hostinfo(&nodemgr_highlevel, host);

        if (hi) {
                HPSB_VERBOSE("NodeMgr: Processing reset for host %d", host->id);
                wake_up_process(hi->thread);
        }
}

static void nodemgr_remove_host(struct hpsb_host *host)
{
        struct host_info *hi = hpsb_get_hostinfo(&nodemgr_highlevel, host);

        if (hi) {
                kthread_stop(hi->thread);
                nodemgr_remove_host_dev(&host->device);
        }
}

static struct hpsb_highlevel nodemgr_highlevel = {
        .name =         "Node manager",
        .add_host =     nodemgr_add_host,
        .host_reset =   nodemgr_host_reset,
        .remove_host =  nodemgr_remove_host,
};

int init_ieee1394_nodemgr(void)
{
        int error;

        error = class_register(&nodemgr_ne_class);
        if (error)
                goto fail_ne;
        error = class_register(&nodemgr_ud_class);
        if (error)
                goto fail_ud;
        error = driver_register(&nodemgr_mid_layer_driver);
        if (error)
                goto fail_ml;
        /* This driver is not used if nodemgr is off (disable_nodemgr=1). */
        nodemgr_dev_template_host.driver = &nodemgr_mid_layer_driver;

        hpsb_register_highlevel(&nodemgr_highlevel);
        return 0;

fail_ml:
        class_unregister(&nodemgr_ud_class);
fail_ud:
        class_unregister(&nodemgr_ne_class);
fail_ne:
        return error;
}

void cleanup_ieee1394_nodemgr(void)
{
        hpsb_unregister_highlevel(&nodemgr_highlevel);
        driver_unregister(&nodemgr_mid_layer_driver);
        class_unregister(&nodemgr_ud_class);
        class_unregister(&nodemgr_ne_class);
}